GB1165076A - Control Mechanism for Typewriters, Calculators, etc. - Google Patents

Abstract

1,165,076. Typewriters; &c. SPERRY RAND CORP. 31 Aug., 1967 [12 Sept., 1966], No. 39948/67. Heading B6F. [Also in Divisions G4 and H1] A control element such as the key of a typewriter, calculator, &c., is biased to its normal position and is held in a control i.e. depressed position by latch means, and the biasing means includes means for operatively coupling the element and the latch means so that the latch means is moved to latching position when the element is moved to the control position. As described, a key 14 Fig. 1, in its latched position closes a switch 11 which may operate so that the up position of the key may represent one binary character and the down position may represent the other binary character. The key stem 15 is mounted on a frame member 16, Fig. 3, by means of a reduced part 20 engaging a slot 17 in a flange 18 on the member 16, and also by a slot 24 in the stem engaging a rod 25 fixed to the member 16 so that the stem has a limited up-and-down movement. Pivoted at 28 on the key stem 15 is a trip arm 27 the pivotal movement of which is limited by the engagement of a lug 30 thereon with the edges of a slot 31 in the key stem. A bail member 32 is pivoted about the rod 25, the pivotal movement being limited by a lug 33 on the bail engaging the edges of a slot 34 in the frame 16. Another lug 40 on the bail 32 can be engaged with the lower edge of a recess 41 in the key stem to hold the key depressed. Two further lugs 35, 36 are provided on the bail 32, which lugs co-operate with the lower edge 37 of the trip arm 27 as described later. The ends 43, 44 of a coil spring 42 engage pins 45, 46 on the arm 27 and bail 32 respectively. In the raised or inoperative position of the key, the spring 42 holds the parts 27, 32 in the positions shown in Fig. 1 and biases the key upwardly with shoulders 22, 23 on the stem abutting against the flange 18. An additional spring 51 with an extending part 52 engaging a slot in the key stem 15 may be provided to reinforce the upward bias. When the key is depressed, the lower edge 37 of the trip arm 27 eventually engages the lug 36 on the bail 32 thus pivoting the bail 32 in a clockwise direction so that lug 40 enters the recess 41 and latches thekeyina lowered position. During this movement, the spring 42 causes the trip arm 27 to be moved clockwise so that its lower edge 37 is now aligned with the bail lug 35. If the key is again depressed, the bail 32 is moved back to its original position and, through the spring 42, causes the trip arm 27 and key also to revert to their original positions Release of the latched down key may be effected without a second depresson of the key by operation of the bail 32 by external means. Such release of a latched-down key e.g. a caseshift key of a typewriter, is often effected by depression of a second key. The key acts upon a leaf spring 48, Fig. 2, attached to a pin 50 and contacting the operating member 13 of the switch 11 so that a mechanical advantage is obtained without an unduly large force being exerted on member 13